Electric switch



p 6, 1955 J. T. MARVIN ELECTRIC SWITCH Filed Sept. 23, 1952 s I l INVENTOR. JOHN Z MARVIN United States PatentO ELECTRIC SWITCH John T. Marvin, Xenia, Ohio, assignor to General Motors Corporation, Detroit, Mich a corporation of Delaware Application September 23, 1952, Serial No. 311,082

8 Claims. (Cl. 200-159) This invention relates to plunger type switches of the type used with doors wherein the door engages a plunger and actuates a switch to open a circuit to a lamp and wherein the switch automatically lights the lamp when the door is opened, and more particularly the invention relates to latch means incorporated in the plunger of this L type of switch so that the plunger may be manually set to break the circuit with the door opened and wherein cam surfaces are provided for automatically turning the plunger so that the switch will be returned to an operative position as the door is closed.

Plunger type switches are used universally for maintaining a circuit open with doors, windows and the like in the closed position and switches of this type operate automatically to cause lamps to burn or sound alarms when the door or windows and the like are opened. On many occasions it is desired to have the doors, windows and the like open without having the lamps burn or having the sound signal operative. The feature of the present invention is to provide an improved plunger type switch with means incorporated in the plunger whereby the plunger can be rotated a certain angular distance to hold the switch with the circuit broken.

Another object of the invention is to provide an improved electrical switch which is adapted for application for use in automobiles, refrigerators, and similar applications where the switch is operated by the opening and closing of a door.

Another object of the present invention is to provide a novel plunger type switch for a current consuming device adapted to be closed each time the door is opened and opened when the door is closed and yet capable of manual manipulation so that the switch can be opened to an open position when the door is opened.

Another obg'ect of the invention is to provide latching means in a plunger type switch for retaining the plunger in a position with the circuit broken while the door is opened and when the door is closed the plunger automatically releases the latching means so that when the door is opened the latching means is ineffective.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred embodiment of the present invention is clearly shown.

in the drawing:

Fig. 1 is a side elevational view of the present invention, but showing certain parts broken away to show the temporary latch in the plunger of the switch.

Fig. 2 is a transverse sectional view taken on line 2--2 of Fig. 1.

Fig. 3 is a transverse sectional view taken on line 3-3 of Fig. 1.

Fig. 4 is a detail showing a longitudinal section through the plunger and taken on line 4-4 of Fig. 1.

Fig. 5 is a transverse sectional view similar to Fig. 2 but showing the contacts of the switch separated.

Fig. 6 is a transverse sectional view similar to Fig. 3

r' ICC but showing the end of one of the contacts of the switch resting on the latch means to retain the switch in the open position.

Fig. 7 is a longitudinal sectional view of a slightly modified form of the switch shown in Fig. 1 and showing a modified spring and latching arrangement.

Fig. 8 is a transverse sectional view taken on line 8-8 of Fig. 7.

Fig. 9 is a view similar to Fig. 8 but showing one of the contacts resting on the latch means to retain the switch in the open position.

Fig. 10 is a view similar to Fig. 1 but shows the switch in the open position.

The switch illustrated in Figs. 1 through 6 includes a plunger or actuator of molded insulating material, such as Bakelite or other suitable moldable plastic. The plunger is formed with a longitudinal recess 23 extending from the inner end thereof. The recess is counterbored to provide a shoulder 17 and the recess is provided with a tapered wall portion 18. The inner end of the plunger is enlarged to provide a collar or head 19. The recess 23 of the plunger has an integral longitudinal projection or rib of inverted V-shaped cross section. The rib is cut out to provide a fiat face 25 and an inclined surface, both surfaces merge with the sloping sides of the rib as shown in Fig. 1.

In the design shown, the switch, which is particularly adapted for door frames of motor vehicles, has the body 22 comprising a cup-like member of metal having an end wall 27 provided with an aperture. A mounting plate 28 is provided with an annular flange 29 which extends through the opening in wall 27 and spun over at 3% against the inside of the wall 27 to hold the plate and body in assembled relation. The plate is adapted to be secured to a suitable metal support, such as a door frame, not

shown.

The inner end of the body or cup-shaped member 22 is closed by a disc 31 of insulating material and the disc 31 is secured in position by tangs 32 extending from the end of the cup-like member 22. A contact member 33, carried by the disc, extends through the center of the cup-like member 22 and the end of the contact member is provided with spaced spherical portions 34 and 35 that slide on the inner surface of the recess 23 in the plunger 20 when the circuit is broken. The spherical portion 34- engages a contact ring 37 positioned on the end of the plunger 26. The movable contact 37 has resilient prongs or fingers 38 which engage the inner wall of the cup-like member 22 so as to ground the movable contact 37 to the door frame through the cup-like member 22 and plate 23 when the plunger is extended outwardly as shown in Fig. 1 in which the circuit is completed and a lamp in the circuit is lighted. The plunger is yieldably held outwardly by a spring 40.

The contact member 33 is secured to the outside of t disc 31 by a rivet 47. and a spring clip 42. is secured to the disc 31 by a rivet 43. The contact member 33 is adapted to be electrically connected with a con act memher, not shown, which is resiliently held against contact member by the clip 42.

In the design illustrated in Figs. 7, 8 and 9 the movable contact instead of having resilient prongs for engaging the walls of the cup-shaped member, a conducting spring is provided which has one end 51 extending into a slot 52 and biased against the wall of the cup-shaped member 22 to provide the ground connection for the switch. If desired, the flat portion 25 may be formed with a groove and the spherical portion 35 may be formed with a dimple which will extend into the groove which will constrain movement of the plunger.

With the parts arranged in their normal positions as illustrated in Fig. 1, the circuit may be broken by pushing the plunger to the right to move the ring contact out of engagement with spherical portion 34. When the plunger has moved a certain distance the portion 34 is carnmed therefrom by the tapered surface onto the cylindrical surface of the recess of the plunger 20. However, if it is desired to open the circuit with the switch parts in their normal positions without the necessity of closing the door or pushing the plunger inwardly or to the right against the biasing force of the spring, the knurled outer end of the plunger may be gripped by the thumb and fore finger of the hand and turned in either direction of rotation until one side of the rib opposite the flat portion cams the spherical portion upon the fiat portion. When that happens the spherical portion 34 will be out of engagement with the ring contact to open the circuit. Should the door be closed wherein the plunger is forced inwardly the spherical portion 35 rides on the slanting portion until it reaches the apex of the rib or before, after which the spherical portion contact rides on one or the other sloping sides of the rib causing the plunger to rotate until the spherical portion rests on the cylindrical surface of the plunger wherein the switch will operate the same as if the latch means had not been incorporated in the switch.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

i. in a push-type switch, the combination comprising, a housing; a plunger having a cavity movable into and out of said housing; a movable contact member controlled by said plunger upon movement thereof; a stationary contact member engageable with said movable contact member in certain normal positions of said plunger; means within said cavity of the plunger for preventing said engagement in said certain normal positions; and additional means within the cavity of the plunger operative upon each movement of said plunger for nullifying the effect of the first named means.

2. In a push-type switch, the combination comprising, a housing; a plunger having a cavity reciprocally movable into and out of said housing; a movable contact member controlled by said plunger upon movement thereof; a stationary contact member engageable with said movable contact member in certain normal positions of said plunger; means located within the cavity of said plunger and operating upon rotative movement of said plunger for preventing said engagement in said certain normal positions; and additional means in said cavity operative upon each reciprocation of said plunger for nullifying the effect of the first named means by causing rotation of the plunger to its initial position.

3. A switch consisting of a housing, a stationary contact in said housing; a movable contact engageable with said stationary contact; a plunger having a cavity reciprocatively carried by the housing and engaged by said movable contact, said plunger provided with a camming surface within the cavity engageable with the stationary contact for disengaging the movable contact from the stationary contact when said plunger is actuated out of its normal position; a projection located Within the cavity of said plunger engageable with the stationary contact in response to turning of said plunger in either direction of rotation in its normal position for holding the stationary contact out of engagement with the movable contact; and a triangular shaped camming surface beyond said projecticn engageable by the stationary contact in response to actuation of said plunger in its turned position for returning said plunger to its normal position.

4. A switch consisting of a housing; a resilient, stationary contact in said housing; a spring loaded movable contact engageable with said stationary contact; a plunger of insulating material reciprocatively carried by said housing and engaged by said movable contact, said plunger having a recess provided with camming surface engageable with the stationary contact for flexing it to disengage the movable contact from the stationary contact when said plunger is actuated out of its normal position; a lon gitudinal projection in the recess of said ringer having a fiat face engageable with the stationary contact in response to turning of said plunger. in its normal position for holding the stationary contact out of engagement with the movable contact; and sloping camming surface on said projection merging with said flat face and engageable by the stationary contact in response to actuation of said plunger in its turned position for returning said plunger rotationally into its normal position.

5. A switch consisting of a metal housing; a plunger of insulating material slidably supported by the housing and having a recess provided with a cylindrical wall at the mouth of the recess and having a tapered wall adjacent said annular recess; a movable Contact supported by the inner end of the plunger and having an annular contact surface extending into the annular wall of the recess and having resilient fingers engaging the housing; a resilient, stationary contact supported by the housing, said contact having one end extending into the recess of said plunger, and engageable with the annular contact surface when the plunger is in its normal position, said tapered wall in said recess operating to flex the stationary contact to disengage the contacts when the plunger is actuated out of its normal position; 'aised flat face in said recess engageable with the free end of the stationary contact upon turning of the plunger in its no ".1 position. for holding the free end of said stationary contact out of engagement with movable contact; and camming sun faces converging toward each other within said recess of said plunger, merging with said flat surface and engageable with the free end of the stationary contact in response to actuation of the plunger in its turned position for returning said plunger rotationaly into its normal position.

6. A switch consisting of a metal housing; a plunger of insulating material slidably supported by the housing. said plunger having an internal recess provided with a tapered wall adjacent the mouth of the recess; a movable contact supported by the inner end of the plunger and having a continuous contact surface extending into the recess of said plunger; a closure for the housing; a resilient contact having one end fixed to the closure and having its free end extending into the recess and engageable with said contact surface within the recess when the plunger is in its normal position, and said tapered wall engageable with the free end of the stationary contact for flexing it to disengage the movable contact when the plunger is moved out of its normal position; a longitudinal rib having sides converging toward each other, said rib being cut out adjacent the tapered portion of said recess to provide a flat face and a camming face extending from the face to the apex of said rib, said flat face engageable with the free end of the stationary contact upon turning of the plunger 21 certain angular distance for holding the stationary contact out of engagement with the movable contact and said camming face engageable by the free end of the stationary contact in response to the actuation of the plunger in the turned position for returning said plunger rotationally into its normal position.

7. A switch consisting of a metal housing; a resilient, stationary contact in said housing; a spring loaded movable contact engageable with the stationary contact and the housing; a plunger reciprocativelv carried by the housing and engageable by said movable contact, said plunger having a camming surface adjacent the mouth of said recess engageable with stationary contact for flexing it to disengage the movable contact when said plunge is actuated out of its normal position; a lon" -iidinal rib of inverted V-shape cross section, said rib b a cut out to provide a flat face engageable with the stationary contact, in response to turning of said plunger in its normal position, for holding the stationary contact out of engagement with the movable contact; and an inclined surface extending from fiat surface to the apex of said rib and engageable with the stationary contact in response to actuation of the plunger in its turned position for returning said plunger rotationally into its normal position.

8. A switch consisting of a metal housing; a resilient, stationary contact in said housing; a plunger of insulating material slidably supported by the housing and having an internal recess; a movable contact member supported by the inner end of said plunger and engageable with the stationary contact; a conducting spring within the housing having one end engageable with the movable contact and having the other end engageable with the housing, said spring serving to keep the plunger in its normal position; and a rib within said recess of said plunger having sloping sides converging toward each other, said rib having a fiat face merging with the sloping side, said flat face engageable with the stationary contact in response to turning of the plunger in either direction of rotation for holding the stationary contact out of engagement with the movable contact and one of said sloping sides adapted to engage the stationary contact in response to actuation of the plunger in its turned position for rotating the plunger into a position so that the contacts will engage each other when said plunger is returned to its normal position.

References Cited in the file of this patent UNITED STATES PATENTS 2,592,660 Crumley Apr. 15, 1952 

